Revision as of 16:00, 11 January 2014

Tables may be authored in wiki pages using either XHTML table elements directly, or using wikicode formatting to define the table. XHTML table elements and their use are well described on various web pages and will not be discussed here. The benefit of wikicode is that the table is constructed of character symbols which tend to make it easier to perceive the table structure in the article editing view compared to XHTML table elements.

As a general rule, it is best to avoid using a table unless you need one. Table markup often complicates page editing.

Wiki table markup summary

table header cell, optional. Consecutive table header cells may be added on same line separated by double marks (!!) or start on new lines, each with its own single mark (!).

|

table data cell, required! Consecutive table data cells may be added on same line separated by double marks (||) or start on new lines, each with its own single mark (|).

|}

table end

The above marks must start on a new line except the double || and !! for optionally adding consecutive cells to a line. However, blank spaces at the beginning of a line are ignored.

XHTML attributes. Each mark, except table end, optionally accepts one or more XHTML attributes. Attributes must be on the same line as the mark. Separate attributes from each other with a single space.

Cells and caption (| or ||, ! or !!, and |+) hold content. So separate any attributes from content with a single pipe (|). Cell content may follow on same line or on following lines.

Table and row marks ({| and |-) do not directly hold content. Do not add pipe (|) after their optional attributes. If you erroneously add a pipe after attributes for the table mark or row mark the parser will delete it and your final attribute if it was touching the erroneous pipe!

Content may (a) follow its cell mark on the same line after any optional XHTML attributes or (b) on lines below the cell mark. Content that uses wiki markup that itself needs to start on a new line, such as lists, headings, or nested tables, must be on its own new line.

Pipe character as content. To insert a pipe (|) character into a table use the <nowiki>|</nowiki> escaping markup

Basics

The following table lacks borders and good spacing but shows the simplest wiki markup table structure.

You type

You get

{|
|Orange
|Apple
|-
|Bread
|Pie
|-
|Butter
|Ice cream
|}

Orange

Apple

Bread

Pie

Butter

Ice cream

The cells in the same row can be listed on one line separated by || (two pipe symbols). If the text in the cell contains a line break, use <br/> instead.

Simple one-pixel table border

The default table formatting uses the "border-collapse: separate" model, which adds table cell spacing (which also separates the table outer border from its content cells). Even with a zero cellspacing, the borders of consecutive cells (and of the overall table container) will add up, so to get a one-pixel separation between cells, you need to selectively remove one or more of the four borders of cells.

Such tables may be formatted more simply, using the "border-collapse: collapse" CSS property; in this table formatting model, the cellspacing attribute (or the CSS "border-spacing:" property) and the table's "padding:" CSS property is ignored and only the larger border of adjacent inner cells (or the table border for outer cells) will be used.

An example of the above for one-pixel table border, using each model (without need for external extensions):

When using the "border-width:" CSS shortcut property, the order of the four space-separated specified values is: top, right, bottom, left. As an example from above:

"border-width: 0 1px 0 0"

When there are fewer than 4 values, the value for left takes its default from the value for right, the value for bottom takes its default from the value for top, and the value for right takes its default from the value for top.

The HTML attributes (such as "width=", "border=", "cellspacing=", "cellpadding=") do not need any length unit (the pixel unit is assumed). The CSS style properties (which override the HTML attributes) require an explicit length unit (if the value is not 0) such as "px" for the pixel.

HTML colspan and rowspan

You can use HTML colspan and rowspan attributes on cells for advanced layout.

This column width is 85% of the screen width (and has a background color)

This column is 30% counted from 85% of the screen width

This column is 70% counted from 85% of the screen width (and has a background color)

Accessibility of table header cells

Table header cells do not explicitly specify which table data cells they apply to (those on their right on the same row, or those below them on the same column). When the table is rendered in a visual 2D environment, this is usually easy to infer.

However when tables are rendered on non-visual media, you can help the browser to determine which table header cell applies to the description of any selected cell (in order to repeat its content in some accessibility helper) using a scope="row" or scope="col" attribute on table header cells. In most cases with simple tables, you'll use scope="col" on all header cells of the first row, and scope="row" on the first cell of the following rows:

Caveats

Negative numbers

If you start a cell on a new line with a negative number with a minus sign (or a parameter that evaluates to a negative number), your table can get broken, because the characters |- will be parsed as the wiki markup for table row, not table cell. To avoid this, insert a space before the value (| -6) or use in-line cell markup (|| -6).

CSS vs attributes

Table borders specified through CSS rather than the border attribute will render incorrectly in a small subset of text browsers.

Common attributes for columns, column groups and row groups

The MediaWiki syntax for tables currently offers no support for specifying common attributes for columns (with the HTML element <col />), column groups (HTML element <colgroup>...</colgroup>) and row groups (HTML elements <thead>...</thead>, <tbody>...</tbody> and <tfoot>...</tfoot>). Those standard HTML elements are not accepted even in their HTML or XHTML syntax.

All the rows and cells (header or data) of the table are rendered within a single implicit row group (HTML element <tbody>...</tbody>) without any attributes or styles.